Polls are open across Germany as the world’s third largest economy chooses a new leader to guide it through an era of febrile immigration debates and souring relations with Washington.

The leading candidate, Friedrich Merz, a conservative who has adopted many of the AfD’s hard-line positions on immigration, used his closing statement of the debate to promise his voters that he would never allow the AfD into his government. Under him, he said, the firewall would hold.